JP2001237792A - Digital radio communications equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the processing quantity of a preprocessor means. SOLUTION: This digital radio communications equipment, provided with a single preprocessor means for performing at least filter processing, is provided with a protocol processing means for selecting processings to be carried out by the preprocessor means from modulation processing or demodulation processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital radio communication apparatus, and is applicable to, for example, demodulation and modulation using a DSP (Digital Signal Processor).

[0002]

2. Description of the Related Art Generally, a conventional radio communication apparatus has a configuration in which a transmission circuit and a reception circuit are separately provided, and a modulation circuit and a demodulation circuit are physically separated.

For example, if a DSP having a limited processing capacity is equipped with a total of two DSPs, one for a transmission circuit (for modulation processing) and one for a reception circuit (for demodulation processing), half-duplex operation is possible. Communication and full-duplex communication can also be performed.

[0004]

However, if two DSPs are mounted on one wireless communication device, the hardware scale may become large, and it is desired to mount only one DSP. . In that case, since the modulation amount and the demodulation process are performed by using one DSP, the processing amount increases. Therefore, the DSP having the limited processing capability has a large load, and the processing may be difficult. is there.

As a method of reducing the processing amount of the demodulation processing of the DSP, it is conceivable to use an undersampling (band sampling) processing as shown in FIG. The undersampling process utilizes the property that when an input signal is sampled, a waveform folded around a half of the sampling frequency appears.

A description will be given with reference to FIG. The IS waveform is the original waveform of the input signal. In order to sample the waveform IS, it must be at least twice the maximum frequency fm of the waveform IS according to the sampling theorem. That is, assuming that the center frequency is f0, (fm =) f0 + BW / 2 = 2
More than twice the frequency.

However, if the sampling frequency fs is taken as shown in FIG. 1, since the fs is smaller than the maximum frequency fm, a waveform folded every fs / 2 appears.
A waveform IS1 obtained by down-converting s appears.

Here, if only the waveform IS1 is extracted using the LPF1 having a filter characteristic as indicated by a broken line, the center frequency of the waveform IS1 is f00.
Since sampling can be performed at the sampling frequency of s / (2f00 + BW), the amount of information is reduced, and the processing amount of the DSP can be reduced.

Although this undersampling process is effective for reducing the amount of demodulation processing performed by the DSP, it cannot reduce the amount of modulation processing performed by the DSP. Therefore, even if the processing amount of the demodulation processing can be reduced to the same extent as the modulation processing by the undersampling processing, the processing amount is twice as large as that when only the modulation processing is performed, in order to simultaneously perform both the demodulation processing and the modulation processing. Is required.

[0010] For this reason, at present, a radio apparatus for performing digital modulation / demodulation by a DSP has been studied, but many are limited to transmission only or reception only.

In consideration of the general characteristics of the DSP as described later, it is generally considered preferable to select the DSP in order to perform the above-described modulation processing and demodulation processing. It is not necessary to limit the components for performing the modulation processing and the demodulation processing to the DSP.

[0012] After all, the problem to be solved by the present invention is:
It can be said that the processing amount required for the modulation processing and the demodulation processing is reduced, and the load on the processing capacity is reduced.

[0013]

According to the present invention, there is provided a digital radio communication apparatus having at least a single preprocessor for performing a filtering process. Is provided with protocol processing means for selecting any one of modulation processing and demodulation processing.

[0014]

(A) Embodiment An embodiment of a digital wireless communication apparatus according to the present invention will be described below.

The features common to the first to third embodiments are as follows.
The processing amount of the DSP is reduced by dispersing the processing for transmission and the processing for reception for one DSP that is used for both the processing for transmission (modulation processing, etc.) and the processing for reception (demodulation processing, etc.). , And DSP.

In general, a DSP is an LSI developed as small and inexpensive hardware capable of executing a large amount of product-sum operations in real time to perform digital signal processing. D
Since the SP is programmable, it can be applied to various kinds of signal processing, and has different algorithms and architectures for digital signal processing from general-purpose microprocessors. DSP algorithms and architectures are unique for high-speed arithmetic processing.
Usually, a hardware multiplier (high-speed multiplication function in general) is provided, and this multiplier (multiplication function) is useful for modulation and demodulation of the digital wireless communication.

(A-1) Configuration of First Embodiment FIG. 1 shows a main part of a digital wireless communication apparatus 10 according to the present embodiment.

In FIG. 1, the digital radio communication device 10 includes a DSP 11, signal lines 12 to 14, and a protocol processing unit (frame processing unit) 15.

The DSP 11 indicated by a broken line is a single DSP in hardware, and has a modulation processing unit 16 and a demodulation processing unit 17 therein. That is, the D
The SP 11 always includes both a modulation processing program MP and a demodulation processing program DP.

The modulation processing section 16 is a section that performs modulation-related processing including modulation (modulation processing) and transmission filter (digital filter) processing.
Is a part for performing demodulation-related processing including demodulation (demodulation processing) and filter processing for reception. These processes are generally realized by a product-sum operation by the above-described hardware multiplier of the DSP 11.

The DSP 11 and three types of signal lines 12 to 1
The protocol processing unit 15 connected by 4 is provided with a function of performing a frame disassembly process at the time of reception, an error control process, a frame assembling process at the time of transmission, and the like. Modulation processing unit 1
6 and the demodulation processing unit 17 are configured by a DSP, whereas the protocol processing unit 15 is an FPGA (Flexible
(Programmable Gate Array) or ASIC.

If possible, the protocol processing unit 15
May also be constituted by a DSP.

The signal line 12 is connected to a protocol processing unit 15
Is a signal line for supplying the baseband transmission data BT output from the to the modulation processing unit 16, and the signal line 13 supplies the baseband reception data BR obtained by the demodulation processing of the demodulation processing unit 17 to the protocol processing unit 15. This is a signal line for performing

The signal line 14 is connected to the protocol processing unit 1
5 transmits and receives the transmission / reception switching information SS from the modulation processing unit 1
6 and a signal line supplied to the demodulation processing unit 17. According to the state of the transmission / reception switching information SS, the modulation processing unit 16 or the demodulation processing unit 17 is alternatively activated, so that the two-way communication performed by the digital wireless communication device 10 can perform either transmission or reception at the same time. This is half-duplex communication that can be performed only by one of them.

Hereinafter, the operation of the present embodiment having the above configuration will be described.

(A-2) Operation of First Embodiment The operation of the digital radio communication apparatus 10 of the present embodiment is shown in FIG.
Shown in FIG. 3 corresponds to, for example, a frame configuration of a mobile station in which the radio access method is TDMA (time division multiple access) in the half-duplex communication method.

As shown in FIG. 3A, the structure of the frame FR processed by the digital radio communication device 10 is the first control slot CS and the first to fourth fourth control slots CS.
It has one time slot 1S to 4S.

As shown in FIG. 3B, the control slot C
Since the transmission / reception state is “reception” from S to the first slot 1S, in FIGS. 3C and 3D, the state of the transmission / reception switching information SS (this state is “reception (that is, reception is present)” of the transmission / reception state or "Send (that is, send)"
Accordingly, only the demodulation processing unit 17 is in the active state and the modulation processing unit 16 is in the inactive state, so that only the demodulation processing is executed, and the modulation processing is not executed.

That is, during this period, the DSP 11
Performs only the demodulation-related processing described above, and does not perform the modulation-related processing.

Similarly, in the second slot 2S, since the transmission / reception state is "transmission" halfway, the transmission / reception switching information SS
Is inverted from the above and indicates the "transmission", only the modulation processing section 16 is in the active state, and the demodulation processing section 17 is in the inactive state. Therefore, during this period, the DSP 11 executes only the modulation-related processing and does not perform the demodulation-related processing.

Next, from the second half of the second slot 2S to the third
Since the transmission / reception state is "reception" up to the middle of the slot 3S, the DSP 11 performs only the demodulation-related processing, and the transmission / reception state is "transmission" from the second half of the third slot 3S to the fourth slot 4S. Only process.

As described above, when the transmission / reception state is “receiving”,
The DSP 11 performs only the demodulation-related processing, and performs only the modulation-related processing at the time of “transmission”.
The SP needs to perform only one of the modulation-related processing and the demodulation-related processing, and the processing amount can be halved.

(A-3) Effect of the First Embodiment As described above, according to the present embodiment, the processing executed by the DSP (11) by inputting the transmission / reception switching information (SS) to the DSP. Since the DSP is selected as one of the modulation-related processing and the demodulation-related processing, the DSP does not execute the modulation-related processing and the demodulation-related processing at the same time. , DSP processing amount (maximum value) can be halved.

(B) Second Embodiment In the following, only differences between the present embodiment and the first embodiment will be described.

In the first embodiment, the DSP 11 always has both the modulation processing program MP and the demodulation processing program DP, but in this embodiment,
In the DSP (21), both the MP and the DP are not mounted at the same time, and only one of them is selectively mounted. Therefore, the transmission / reception state of this embodiment is “receiving”,
Either “transmission” or “guard time” for loading MP or DP.

(B-1) Configuration and Operation of Second Embodiment FIG. 4 shows a main part of a digital radio communication device 20 of the present embodiment.

In FIG. 4, the digital radio communication apparatus 20 includes a DSP 21, signal lines 12, 13, 24,
Memory 28, protocol processing unit (frame processing unit) 2
5 is provided.

The functions of the components 12 and 13 having the same reference numerals as those in FIG. 1 are the same as those in FIG.

The memory 28 is a memory for storing the modulation processing program MP and the demodulation processing program DP described above.

Other components 21, 24, 25, 28
Are basically the same as the corresponding parts in FIG.

That is, the modulation and demodulation processing unit 21
11, the signal line 24 corresponds to the signal line 14,
The protocol processing unit 25 corresponds to the protocol processing unit 15.

The modulation / demodulation processing unit 21 includes a DSP 11
Although it is composed of one DSP as in
The mode switching unit 29 that did not exist in the DSP 11
It is equipped with.

The mode switching section 29 is a section that receives the transmission / reception switching information SS1 supplied from the protocol processing section 25 using the signal line 24 and switches the operation mode of the DSP 21. The switching of the operation mode is performed among three modes: a modulation mode (corresponding to the “transmission”), a demodulation mode (corresponding to the “reception”), and a guard time mode. That is, the mode switching unit 29 controls the DSP 21,
Switch to demodulation mode in response to "Receive" of SS1,
Switching to the modulation mode in response to No. 1 “transmission” and switching to the guard time mode in response to SS1 “guard time”.

In the guard time mode when switching from the demodulation mode to the modulation mode, the mode switching unit 29 reads the modulation processing program MP read from the memory 28.
Is written into the control storage means 30 in the DSP 21, and in the guard time mode when switching from the modulation mode to the demodulation mode, the demodulation processing program DP read from the memory 28 is written into the control storage means 30.

Since the guard time mode of this embodiment corresponds to the guard time required for reading and writing of MP and DP, it is in a state where neither effective modulation-related processing nor demodulation-related processing can be performed.

The protocol processing unit 25 has the same frame decomposing function as the protocol processing unit 15 described above.
In addition to assembling and error control functions, it also recognizes the guard time, and
It has a function of outputting transmission / reception switching information SS1 that can take three states of “transmission” and “guard time”.

The digital radio communication device 20 as described above
When the transmission / reception switching information SS1 output from the protocol processing unit 25 is in the “reception” state, the modulation / demodulation processing unit 2
1 and the protocol processing unit 25 perform the receiving operation RW1 shown in FIGS. This receiving operation RW
In step 1, an effective receiving operation (such as demodulation-related processing by the DSP 21 or frame decomposition processing by the protocol processing unit 25) is performed. Therefore, at this time, the demodulation processing program DP is stored in the control storage means 30.

Next, when the state of the transmission / reception switching information SS1 is switched to "guard time", the digital radio communication device 20 enters the guard time state GB1 and the modulation processing program MP is read from the memory 28 and stored for control. Written in the means 30.

After the reading / writing is completed, the state of the transmission / reception switching information SS1 changes from the “guard time” state to the “transmission” state, and the digital radio communication device 20
Shifts to the transmission operation SW1. In this transmission operation SW1, an effective transmission operation (modulation-related processing by the DSP 21 and frame assembly processing by the protocol processing unit 25, etc.)
Is performed.

Further, when the state of the transmission / reception switching information SS1 is switched to "guard time", the digital radio communication device 20 shifts to the guard time state (GB2) again,
The demodulation processing program DP is read from the memory 28 and written into the control storage means 30. After the guard time GB2 has elapsed, the valid reception operation RW2 is performed again.

Thereafter, the same operation is repeated according to the state of the transmission / reception switching information SS1.

(B-2) Effects of the Second Embodiment As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained.

In this embodiment, the DSP (21)
Since the configuration is such that the modulation processing program and the demodulation processing program are loaded into the DSP from the memory (28) arranged outside the DSP, variations in configuration and operation can be provided.

(C) Third Embodiment Hereinafter, only the points of this embodiment different from the first and second embodiments will be described.

In the first and second embodiments, the two-way communication can support only half-duplex communication. However, in this embodiment, the half-duplex communication can be performed while reducing the processing amount of the DSP. Can also support full-duplex communication.

Therefore, the transmission / reception state of this embodiment cannot be expressed only by the above-mentioned “reception”, “transmission”, and “guard time”.
"With transmission", "without transmission", and "guard time"
5 ways are required. Moreover, this guard time is different from the second embodiment in that it is a complex guard time in which a plurality of circuit operation states (operation modes) are included.

(C-1) Configuration and Operation of Third Embodiment FIG. 6 shows a main part of a digital wireless communication apparatus 40 according to this embodiment.

In FIG. 6, a digital radio communication apparatus 40 includes a modulation / demodulation processing section (DSP) 41 and a signal line 1.
2, 13, 44, a memory 28, a protocol processing unit (frame processing unit) 45, and a reception buffer 52.

The functions of the components 12, 13, and 28, which are denoted by the same reference numerals as those in FIG. 4, are the same as those in FIG.

The functions of the other components 41, 44 and 45 are basically the same as those of the corresponding parts in FIG.

That is, the modulation and demodulation processing unit 41
21, the signal line 44 corresponds to the signal line 24,
The protocol processing unit 45 corresponds to the protocol processing unit 25.

Among them, the modulation / demodulation processing unit 41
And a mode switching unit 49 and a control storage unit 50 as in the case of the DSP 21, but additionally includes a reception buffer control unit 51.

Here, the control storage means 50 is
The control storage unit 30 according to the second embodiment is a storage unit that can simultaneously store both the modulation processing program MP and the demodulation processing program DP when necessary.
Is different from

The function of the mode switching unit 49 is also different from that of the mode switching unit 29.

That is, the mode switching unit 29 only changes the operation mode of the DSP 21 according to the supplied transmission / reception switching information SS1, but the mode switching unit 49 of the present embodiment changes the operation mode according to the transmission / reception switching information SS2. DS
In addition to changing the operation mode of P41, the operation mode is also changed according to the control from the reception buffer control unit 51.

The reception buffer control section 51 is a section for controlling the buffering processing for the reception buffer 52. In the buffering process of the reception buffer 52, the reception data received by the digital wireless communication device 40 from the destination communication device is temporarily stored in the reception buffer 52 under the control of the reception buffer control unit 51, and the reception buffer control unit The data is read from the reception buffer 52 according to the control from the reception buffer 51.

The state of the transmission / reception switching information SS2 itself is also different from that of the transmission / reception switching information SS1. Since the second embodiment was able to cope only with half-duplex communication, the transmission / reception switching information SS1 includes “reception”,
Although it was sufficient to specify three types of “transmission” and “guard time”, the present embodiment supports both half-duplex communication and full-duplex communication.
It is necessary to specify five types: “with reception”, “without reception”, “with transmission”, “without transmission”, and “guard time”.

The reception buffer control unit 51 controls the buffering process in accordance with the transmission / reception switching information SS2 or in accordance with a preset procedure. Are specified simultaneously (equivalent to full-duplex communication)
In this case, it is necessary to write received data to the reception buffer 52 without fail.

Since the full-duplex communication of the present embodiment is realized with the same processing amount (of the DSP 41) as that of the half-duplex communication, the reception data is not demodulated during the full-duplex communication without being demodulated. The transmission data is stored in the reception buffer 52, and when the transmission data is interrupted, the reception data stored in the reception buffer 52 is read and demodulation-related processing is performed.

That is, during full-duplex communication, the DSP 41
Performs the modulation-related processing preferentially, and performs the demodulation-related processing at a guard time when the processing amount is small. This is because the processing related to reception may be performed in accordance with the internal state of each communication device that has received, but the processing related to transmission needs to be performed at a required timing in accordance with the device of the communication partner.

Therefore, the DSP 21 of the second embodiment
Are three operation modes: modulation mode, demodulation mode, and guard time mode.
In addition to the three operation modes, the three operation modes include a buffering mode, a buffering modulation mode, and a guard time demodulation mode, and there are a total of six operation modes.

The buffering mode is a mode in which only the received data is stored in the buffering process.

The buffering modulation mode is a mode in which buffering processing (accumulation of received data) and modulation-related processing are simultaneously performed. Since the buffering process here merely stores the received data in the reception buffer 52, the buffering process can be executed together with the modulation-related process with almost no load on the processing capability of the DSP 41.

Further, the guard time demodulation mode is an operation mode in which the digital radio communication device 20 does not transmit to the communication device of the other party and does not receive from the communication device of the other party. , A mode in which buffering processing (reading of stored received data) and demodulation-related processing are performed. This is different from the guard time mode of the second embodiment in which only the MP and DP are read and written, and neither effective modulation-related processing nor demodulation-related processing is performed.

FIG. 7 shows the operation of the digital radio communication device 40 of the present embodiment as described above.

In FIG. 7, in the digital radio communication apparatus 40 of the present embodiment, when the state RR1 of the transmission / reception switching information SS2 indicates “with reception” and “without transmission”, the data is stored in the control storage means 30 of the DSP 41. Is loaded with a demodulation processing program DP, and demodulation-related processing is executed.

In this state RR1, the DSP 41 performs demodulation-related processing on the received data without using the reception buffer 52, as in the second embodiment. This is a process corresponding to the demodulation mode.

Thereafter, when the transmission / reception switching information SS2 specifies "(complex) guard time", the operation mode of the DSP 41 is changed to the guard time GB10. In the guard time GB10, no buffering processing and no demodulation-related processing are performed because the buffering is not performed in the previous state RR1. This is a process corresponding to the guard time mode.

Next, the state R after the guard time GB10 has passed
In R2, the “received” and “not transmitted” states are the same as in RR1, but here, the DSP 41 stores the received data in the reception buffer 52 (buffering) under the control of the reception buffer control unit 51. ) And the demodulation-related processing is not performed. This is a process corresponding to the buffering mode.

Here, whether or not to shift to such a buffering mode is determined according to the control information transmitted by the destination communication apparatus, the processing procedure stored in advance in the reception buffer control unit 51, and the like. Can be.

Guard time GB11 following state RR2
Then, the reception data accumulated in RR2 is stored in the reception buffer 52.
In addition to performing the demodulation-related processing of the received data, according to the transmission / reception switching state SS2, the modulation processing program MP used in the subsequent state RR3 and the demodulation processing program DP used in the state GB12 are used for control. Write to the storage means 30. This is a process corresponding to the guard time demodulation mode.

The state RR3 is a state corresponding to full-duplex communication of “with reception” and “with transmission”. At this time, D
The SP 41 stores the received data in the reception buffer 52 and executes the modulation process. This is a process corresponding to the buffering modulation mode.

Next, in the guard time GB12, the state RR3 is determined by using the demodulation processing program DP already written in the control storage means 30 in GB11.
Executes the demodulation-related processing on the reception data stored in the reception buffer 52. This is a process corresponding to the guard time demodulation mode.

Finally, in the state RR4, in response to the “no reception” and “transmission” of the transmission / reception switching state SS2, the DS
P41 executes only the modulation-related processing. This is a process corresponding to the modulation mode.

FIG. 7 shows only an example of the operation. Thus, for example, after state GB2, state R
A modification in which the state RR4 is arranged instead of R2 is also possible. For example, whether to write the demodulation processing program DP into the control storage means 30 in the guard time demodulation mode depends on the context of the procedure. Change.

(C-2) Effects of the Third Embodiment As described above, according to the present embodiment, the same effects as those of the second embodiment can be obtained.

In addition, in the present embodiment, the first and second
It is possible to realize full-duplex communication that could not be realized in the first embodiment while suppressing the processing amount of the DSP.

(D) Other Embodiments As specific examples of the digital radio communication devices 10 and 20 of the first and second embodiments, radio devices using digital modulation / demodulation processing and half-duplex communication are used. It can be widely applied to those that adopt the method.

In particular, the present invention is suitably applied to a device that requires low cost and low power consumption, such as an ITS on-board terminal and a PHS terminal.

Similarly, the digital radio communication device 40 of the third embodiment is a radio device using digital modulation / demodulation processing, and is a half-duplex communication system (for example, “with reception” in the transmission / reception switching state SS2). If "with transmission" is not selected, the third embodiment can be used for half-duplex communication as it is and can be widely applied to those employing the full-duplex communication method.

In the first to third embodiments, the DSP
However, the application of the present invention is not limited to the DSP.
For example, if the processing speed of the one-chip microcomputer is sufficiently improved in the future,
It is also possible to replace with a chip microcomputer.

Further, it is considered that the present invention is effective when used in combination with the undersampling processing described above.
It is not necessary.

In short, the present invention supports a plurality of communication systems using one circuit configuration by changing the operation logic corresponding to the circuit characteristics (such as the DSP) according to the contents of the software for loading. It can be widely applied to software radio systems that can be used.

In the software radio system, for example, a code specifying a communication system added to the header of the received data on the transmitting side is read on the receiving side, read from a memory (for example, corresponding to the memory 28), and loaded. Program (equivalent to the MP or DP)
A plurality of communication systems can be automatically supported.

For example, in addition to the above-described distinction between MP and DP, a plurality of types of MP, for example, M
It is possible to store P1 and MP2 in a memory in advance and select whether to load MP1 or MP2 according to the code added on the transmission side.

Therefore, when the present invention is applied to, for example, a portable telephone, it is possible to cope with different wireless telephone systems around the world or to add a communication system which can be used as an upgrade.

[0097]

As described above, according to the present invention, the amount of processing executed by the preprocessor at one time can be reduced.

Thus, for example, it is possible to reduce the size of the preprocessor means, etc., and to realize a small scale, low price, and low power consumption of a digital radio communication device equipped with the preprocessor. It is possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a main part of a digital wireless communication device according to a first embodiment.

FIG. 2 is an explanatory diagram of an undersampling process.

FIG. 3 is an operation explanatory diagram of the first embodiment.

FIG. 4 is a block diagram illustrating a configuration of a main part of a digital wireless communication device according to a second embodiment.

FIG. 5 is an operation explanatory diagram of the second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a main part of a digital wireless communication device according to a third embodiment.

FIG. 7 is an operation explanatory diagram of the third embodiment.

[Explanation of symbols]

10, 20, 40 ... Digital wireless communication device, 11, 12
1, 41 DSP, 15, 25, 45 protocol processing unit, 28 memory, 52 reception buffer.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K018 AA04 BA01 BA03 JA03 5K028 AA07 BB04 CC02 HH00 SS23 SS24 5K034 AA11 EE03 FF05 FF13 GG05 HH63 KK02

Claims (3)

[Claims] 1. A digital radio communication apparatus having at least a single preprocessor for performing at least a filter process, wherein a protocol processor selects a process performed by the preprocessor from a modulation process or a demodulation process. A digital wireless communication device comprising: 2. The digital wireless communication apparatus according to claim 1, wherein: control information for modulation processing describing the content of the modulation processing;
A control information storage unit for storing demodulation process control information describing the content of the demodulation process, and the preprocessor unit includes a function switching unit that changes a function according to the supplied control information, The protocol processing unit supplies either the modulation processing control information or the demodulation control information to the function switching unit according to a selection regarding processing performed by the preprocessor. Communication device. 3. The digital wireless communication apparatus according to claim 2, further comprising a receiving temporary storage unit for temporarily storing reception information received from a communication partner, and performing reception and transmission simultaneously. In this case, the protocol processing unit prioritizes the modulation process corresponding to the transmission, and after the transmission is completed, performs the demodulation process using the reception information read from the reception temporary storage unit. A digital wireless communication device, wherein the selection is performed.